Overhead projection screen holder

ABSTRACT

A holder for mounting a projection screen against a wall in such a manner that the top of the screen may be moved outwardly from said wall to incline the screen, said holder consisting of an arm adapted to lie vertically against a wall, a link pivoted at its upper end to said wall above said arm, and at its lower end to the midpoint of said arm, on horizontal axes parallel to the wall, whereby said arm may be inclined outwardly from the wall with its lower end engaging the wall, the upper edge of the screen being attached to the upper end of said arm, and a generally vertical bar attached to the lower end of said arm and extending downwardly therefrom, whereby said arm may be manipulated, the lower edge of said screen being attachable to the lower end of said bar.

United States Patent [72] Inventor Ambrose M.Jennings Box 176, Basehor,Kans. 66007 [21] Appl.No. 759,109 [22] Filed Sept.11, 1968 [45] PatentedMar. 2, 1971 [54] OVERHEAD PROJECTION SCREEN HOLDER 8 Claims, 5 DrawingFigs.

[52] U.S.Cl 248/284, 160/23 [51] 1nt.Cl ..G03b 21/56 [50] Field ofSearch 248/284, 286, 293, 291, 324, 489, 495, 496; 160/23, 24, 29;

. 35/63 v 56] References Cited UNITED STATES PATENTS 2,229,472 1/1941Raven l60/24X 2,825,152 3/1958 Baylon 35/63 3,309,049 3/1967 Albee160/24X FOREIGN PATENTS 676,403 2/1930 France Primary Examiner-Roy D.Frazier Assistant Examiner-J. Franklin Foss Attorney-John A. HamiltonABSTRACT: A holder for mounting a projection screen against a wall insuch a manner that the top of the screen may be moved outwardly fromsaid wall to incline the screen, said holder consisting of an armadapted to lie vertically against a wall, a link pivoted at its upperend to said wall above said arm, and at its lower end to the midpoint ofsaid arm, on horizontal axes parallel to the wall, whereby said arm maybe inclined outwardly from the wall with its lower end engaging thewall, the upper edge of the screen being attached to the upper end ofsaid arm, and a generally vertical bar attached to the lower end of saidarm and extending downwardly therefrom, whereby said arm may bemanipulated, the lower edge of said screen being attachable to the lowerend of said bar.

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()VERHEAD PRQJEQTION SCREEN HOLDER This invention relates to new anduseful improvemenm in projection screen holders, and has particularreference to pro jection screens mounted in overhead positions.

In classrooms, it is common practice for an instructor to remain seatedat his desk at the front of the classroom, with a slide, movie or otherprojector on the desk before him and to project pictures or otherinstructional material rearwardly and upwardly over his head to a screenmounted high on the room wall behind him. This allows him to lecturefrom the front of the room, and to control and operate the projector atthe same time. Projectors suitable for this purpose are commerciallyavailable. However, this type of projection is subject to certaindifficulties if the screen is suspended vertically against the wall inthe usual manner. Since the image is then projected upwardly at an acuteangle to the screen surface, the top portion of the screen is fartherfrom the projector than the lower portion of the screen, and the topportion of the projected image is wider than the lower portion oftheimage; This type of distortion is commonly known as a keystoneeffect, and is of course highly objectionable. Also, since the upper andlower portions of the screen are at different distances from'theprojector, it is often impossible to keep the entire projected imageclear and sharply focused.

Certain types of overhead projection screen holders have been proposedfor overcoming the across-the-room and focusing difficulties, bypermitting inclining of the screen so as to be generally normal to theaxis of the projected beam, but all of these within my knowledge havealso-been subject to certain objectionable features, in that they havebeen relatively complicated and expensive structures, or .that theyrequire the screen to be set at all times well out from the wall so asto be in the way and to constitute an eyesore, or that they aredifficult to operate or manipulate by an operator standing on the floor,since the screen is preferably positioned substantially at ceiling leveland classroom ceiling are often eleven feet. or more above the floor.Also, screens mounted at this high elevation are not generally desirablefor use with ac'ross-the-room projectors, which generally require alower screen, so that the use of such an across-the-room projectorgenerally requires a separate screen. r

Accordingly, the object of the present invention is the provision of anoverhead projection screen holder which eliminates all of the aboveenumerated objectionable features of previous holders, in that, it notonly permits inclination of the screen to eliminate keystoning andfocusing difficulties, but also is extremely simple and economical ofstructure, permits the screen to be stored flat against the wall, oreven reeled up in a reel case, when not in use, which is easily operableby an operator standing on the floor, and which permits lowering of thescreen to an elevation suitable for use with across-the-room projectors.

In summary, these objects are accomplished by a screen holder consistingof an arm which is normally verticaland lies flat against the wallwith-its upper end substantially 'at the ceiling level, the screen caseextending horizontally and being affixed to the upper end of saidarm sothat the screen may be extended downwardly therefroma link pivoted atits upper end to the ceiling or wall and at its lower end to themidpoint of said arm,'whereby the upper end of said arm maybe movedoutwardly from the wall by pushing upwardly on the lower end thereof,and a pusher-bar adapted to be attached to the lower end of said arm andto lie vertically against the wall, whereby said arm may be manipulated,the lower edge of said screen being attachable to the lower end of saidpusher bar. When detached from the arm, the pusher bar may be; utilizedas a grapple to reach and extend the screen from its case. The arm maybe concealed by a decorative plaque secured thereto when the screen isnot in use. Also, the arm may be reversed by pivoting it on said link tobring the screen case to the lower end thereof, so that the screen maybe extended for use at a lower elevation for use with across-the-roomprojectors.

With these objects in view as well as other objects which will appear inthe course of the specification, reference will be had to theaccompanying drawing, wherein:

FIG. I. is a front elevational view. partially broken away, of anoverhead projection screen holder embodying the present invention,operatively mounted on a classroom wall, with a screen case mounted onthe holder, but with the screen retracted into said case;

FIG. 2 is a fragmentary sectional view taken on line II--II of F 1G. 1,with parts left in elevation;

FIG. 3 is a view similar to FIG. 2, but with the screen extended andinclined for use with an overhead projector;

FIG. 4. is a view similar to. FIG. 2 but with the screen positioned foruse with an across-the-room projector; and

FIG. 5 is a reduced sectional view taken on line V-V of FIG. 1, showingthe relationship of the screen to an overhead projector.

1 Like reference numerals apply to similar parts throughout the severalviews, and referring principally to FIG. 5, the numeral 2 applies to aprojector resting on the instructor's desk 4 at the front of a classroomhaving a front wall 6, ceiling 3 and floor 10, said projector beingoperable to project an image of instructional material to a projectionscreen 12 disposed high on wall 6. Thus the instructor may sit at hischair 14 before the desk, facing his class, and simultaneously operatethe projector, deliver his lecture, and refer by pointer or the like todetails of the projected image. The screen 12, as shown, is pliable andis wound on a spring reel mounted in a rigid cylindrical case l6, sothat it maybe extended downwardly from said case by pulling downwardlythereon in the manner of an ordi narywindow shade. The spring reel isalso ordinarily provided with a ratchet mechanism for. retaining thescreen releasably at any desired degree of extension from the case. Thisstructure is common and well known in the art, and is therefore notshown. The screen is provided along its lower edge with a stiffening bar15 provided at its midpoint with a pull loop 17 which may be grasped toextend the screen manually.

The screen holder forming the subject matter of the presentinvention'includes an arm 18 adapted normally to lie vertically againstwall 6, with its upper end closely adjacent ceiling 8. As shown, saidarm consists of a pair of parallel side rails 20 rigidly joinedintermediate their ends by a block 22. Adjacent the lower end of thearm, a rod 24 extends transversely between and is affixed at its ends inside rails 20. Screen case 16 is affixed to the upper end of arm 18, atthe side thereof away from wall 6, as by screws 26. Said screen case isdisposed horizontally and parallel to wall 6.

- Arm 18 is supported by a link 28 of inverted U-form. The arms 30 ofsaid link are engaged pivotally. in side rails 20 of arm 18, at themidpoint of said arm, on a horizontal transverse axis, these pivotalconnections being indicated at 32, and the base portion 34 of said link,which is parallel to the axis of pivots 32, is engaged pivotally in apair of hooks 36 fixed in a bar 38;, said bar being affixed towall 6, atits juncture with ceiling 8, as by screws 40. When'the screen 12 isretracted within its case 16, as shown in FIGS. 1 and 2, arm 18 ofcourse extends well below case 16 and would be unsightly when the screenis not in use, if means were not provided to conceal it. For thispurpose, there is provided a planar plaque 42 affixed to the forwardside of arm 18. Horizontally, this plaque may be of any desired width,while vertically it extends from a point just below screen case 16 to apoint just above crossrod 24$ of the arm. Said plaque may carry apicture or other decorative matter on its outer surface. i

The screen holder also includes an elongated pusher bar or lever 44adapted to be positioned between side rails 20 of arm 13, paralleltherewith, and to extend beneath the lower end of said arm as shown inFIG. 1. Said pusher bar is provided intermediate its ends with aforwardly opening notch 46 adapted to be engaged over crossrod 24 of arm18, and carries at its upper end of roller 48 rotatable on a horizontaltransverse axis and adapted to move in rolling contact with room wall 6.At its lower end, bar 44 has a hook 50 affixed thereto.

When the screen is not in use, the parts have the position shown inFIGS. 1 and 2, except that at this time pusher bar 44 is normallydetached from rod 24 and laid aside. If it were not, it would extenddownwardly overthe blackboard of the classroom, said blackboard beingindicated at 52, which would of course be objectionable. To position thescreen for use, the operator first takes pusher bar 44, reversed so thathook 50 thereof is uppermost, and reaches upwardly to engage said hookin pull loop 17 of the screen, then pulls downwardly to extend screen 12from its case 16. The length of the pusher bar is such that thisoperation may be performed easily by a person of ordinary height, evenif screen case 16 is perhaps eleven feet above the floor. The operatorthen reverses the pusher bar so that roller 48 thereof is uppermost, andengages notch 46 thereof over crossrod 24 of arm 18, as shown.

The operator then pulls the lower end of pusher bar 44 slightlyoutwardly from wall 6, whereby said bar acts as a lever to move thelower end of arm 18 away from the wall and to press roller 48 againstwall 6, and pushes upwardly on said pusher bar. This causes the upperend of arm 18, which is supported by link 28, to move outwardly fromwall 6 as'shown'in FIG. 3. Outward initial movement, rather thanmovement toward and against wall 6, is assured by the weight of screencase 16 at the outer side of said am. The higher pusher bar 44 israised, the more nearly arm 18 approaches a horizontal position. Duringthis movement, the lower end of arm 18 is held out of engagement withwall 6 by the pusher bar, which is in turn supported against wall 6 byroller 48. Thus arm 18 does not slide frictionally on the wall, andscratching or marring of the wall which otherwise would occur isprevented. Also, it will be seen that while arm 18 is thus turned in acounterclockwise direction on link pivots 32 at this time, as viewed inFIG. 3, and that screen case 16 is thus lowered with respect to saidpivots, nevertheless pivots 32 aresimultaneously elevated with respectto link pivot 34 bythe angular movement of the link. Thus screen case 16remains at a generally uniform elevation regardless of the angle of arm18. This is a distinct advantage over certain other screen holders,which permit adjustment of the screen angle only by bodily raising andlowering of the entire screen.

When arm 18 has been moved to the desiredangle, the lower end of pusherbar 44 is moved toward wall 6 to allow the lower end of arm 18 to engagewall 6 at the point 54 indicated in FIG. 3. The friction of thisengagement, plus the counterclockwise (as viewed in FIG. 3) torqueexerted on said arm by the weight of the screen and screen case, isample to prevent slippage of the armagainst the wall, at all times afterthe arm has reached a certain minimum inclination relative to the wall,so that the arm remains fixed in the adjusted position. The depth ofnotch 46 of bar 44 must of course be sufficient to allow contact of arm18 with wall 6 without obstruction by bar 44.

The pull loop 17 of the screen is then engaged on hook 50 at the lowerend of pusher bar 44, and the screen is ready for use, supported at theproper angle for use with projector 2. If the screen is slack at thistime, due to inaccurate original extension thereof from its case 16, itmay be tightened by a slight pull on its lower edge to release theratchet mechanism of the spring reel in case 16, whereupon the screen istightened and held taut by the reel. Alternatively, screen pull loop 17can be attached to hook 50 before arm 18 is tilted at all, so thatpusher bar 44 is raised with the screen already attached thereto. Also,the angle of the screen can be adjusted at any time during use, byraising or lowering pusher bar 44.

As shown in FIG. 4, the present holder also permits lowering of thescreen on wall 6, as may be desirable for use with across-the-roomprojectors. For this purpose, arm 18 is pivoted 180 on link pivots 32,so that crossrod 24 thereof is adjacent link pivot 34, and screen case16 is at the lower end of the arm, against wall 6. Pusher bar 44 is notutilized in this case. Screen 12, when extended from its case 16, thendepends vertically from the case, flush against wall 6, but with itsoperative surface still facing outwardly toward the room, as seen inFIG. 4.

While I have shown and described a specific embodiment of my invention,it will be readily apparent that many minor changes of structure andoperation could be made without departing from the spirit of theinvention as defined by the scope of the appended claims.

lclaim:

1. An overhead projection screen holder comprising:

a. an arm adapted normally to lie vertically against a room wall;

b. means for attaching the upper edge of a projection screen to theupper end of said arm, at the side thereof outward from said wall;

c. a normally vertical link pivoted at its lower end to said arm on ahorizontal transverse axis intermediate the ends of the latter;

d. means for pivotally connecting the upper end of said link to saidwall on a fixed horizontal transverse axis adjacent the upper end ofsaid arm; and

e. means carried at the lower end of said arm for engaging the loweredge of said screen, .whereby as the lower end of said arm is raisedupwardly along said wall, the upper end of said arm is moved outwardlyfrom said wall and said screen is inclined outwardly and downwardly fromsaid wall, the lower end of said arm being urged against said wall bythe weight of said screen and being prevented from moving relative tosaid wall by its frictional engagement therewith.

2. An overhead projection screen holder as recited in claim I whereinsaid link is pivoted to said arm substantially at the midpoint of thelatter, and wherein said arm is substantially twice the length of saidlink, whereby the upper end of said arm remains at a generally uniformelevation relative to said wall regardless of the degree to which saidarm may be inclined.

3. An overhead projection screen holder as recited in claim 1 with theaddition of means for moving the lower end of said arm vertically onsaid wall, said means comprising:

a. an elongated lever adapted to lie vertically against said wall andbeing pivoted intermediate its ends, on a horizontal transverse axis, tothe lower end portion of said arm; and

b. a roller carried at the upper end of said lever for rotation on ahorizontal transverse axis and adapted to engage said wall, wherebymovement of the lower end of said lever outwardly from said wall willforce the lower end of said arm away from said wall to be supportedrelative to said wall only through said lever and said roller.

4. An overhead projection screen holder as recited in claim 3 whereinthe lower end of said arm extends downwardly beyond its pivotalconnection to said lever to a sufficient degree to project beyond saidlever toward said wall when said arm is inclined, so as to be engageablewith said wall without interference by said lever.

5. An overhead projection screen holder as recited in claim 3 whereinsaid lever is detachably pivoted to said arm to be easily separatedtherefrom.

6. An overhead projection screen holder as recited in claim 4 whereinsaid arm is. provided adjacent its lower end with a horizontally andtransversely extending crossrod engageable in a notch formed in saidlever and opening outwardly from said wall, whereby said lever isdetachably pivoted to said arm.

7. An overhead projection screen holder as recited in claim 3 havingmeans at the lower end of said lever for releasably engaging the loweredge of said screen.

8. An overhead projection screen holder as recited in claim .6 for usein connection with a pliable projection screen normally reeled in a casecarried at the upper end of said arm and extendable downwardly from saidc se, and wherein said lever is provided at its lower end with a hook towhich the lower edge of said screen is attachable when extended, saidlever being reversible when detached from said arm for use with saidhook uppermost as a tool to reach and extend said screen from said case.

1. An overhead projection screen holder comprising: a. an arm adaptednormally to lie vertically against a room wall; b. means for attachingthe upper edge of a projection screen to the upper end of said arm, atthe side thereof outward from said wall; c. a normally vertical linkpivoted at its lower end to said arm on a horizontal transverse axisintermediate the ends of the latter; d. means for pivotally connectingthe upper end of said link to said wall on a fixed horizontal transverseaxis adjacent the upper end of said arm; and e. means carried at thelower end of said arm for engaging the lower edge of said screen,whereby as the lower end of said arm is raised upwardly along said wall,the upper end of said arm is moved outwardly from said wall and saidscreen is inclined outwardly and downwardly from said wall, the lowerend of said arm being urged against said wall by the weight of saidscreen and being prevented from moving relative to said wall by itsfrictional engagement therewith.
 2. An overhead projection screen holderas recited in claim 1 wherein said link is pivoted to said armsubstantially at the midpoint of the latter, and wherein said arm issubstantially twice the length of said link, whereby the upper end ofsaid arm remains at a generally uniform elevation relative to said wallregardless of the degree to which said arm may be inclined.
 3. Anoverhead projectIon screen holder as recited in claim 1 with theaddition of means for moving the lower end of said arm vertically onsaid wall, said means comprising: a. an elongated lever adapted to lievertically against said wall and being pivoted intermediate its ends, ona horizontal transverse axis, to the lower end portion of said arm; andb. a roller carried at the upper end of said lever for rotation on ahorizontal transverse axis and adapted to engage said wall, wherebymovement of the lower end of said lever outwardly from said wall willforce the lower end of said arm away from said wall to be supportedrelative to said wall only through said lever and said roller.
 4. Anoverhead projection screen holder as recited in claim 3 wherein thelower end of said arm extends downwardly beyond its pivotal connectionto said lever to a sufficient degree to project beyond said lever towardsaid wall when said arm is inclined, so as to be engageable with saidwall without interference by said lever.
 5. An overhead projectionscreen holder as recited in claim 3 wherein said lever is detachablypivoted to said arm to be easily separated therefrom.
 6. An overheadprojection screen holder as recited in claim 4 wherein said arm isprovided adjacent its lower end with a horizontally and transverselyextending crossrod engageable in a notch formed in said lever andopening outwardly from said wall, whereby said lever is detachablypivoted to said arm.
 7. An overhead projection screen holder as recitedin claim 3 having means at the lower end of said lever for releasablyengaging the lower edge of said screen.
 8. An overhead projection screenholder as recited in claim 6 for use in connection with a pliableprojection screen normally reeled in a case carried at the upper end ofsaid arm and extendable downwardly from said case, and wherein saidlever is provided at its lower end with a hook to which the lower edgeof said screen is attachable when extended, said lever being reversiblewhen detached from said arm for use with said hook uppermost as a toolto reach and extend said screen from said case.